Lerach Coughlin Stoia Geller Rudman & Robbins LLP Files Class Action Suit Against Sonus Networks, Inc.

Lerach Coughlin Stoia Geller Rudman & Robbins LLP("Lerach Coughlin") (http://www.lerachlaw.com/cases/sonus/) todayannounced that a class action lawsuit has been commenced on behalf ofan institutional investor in the United States District Court for theDistrict of Massachusetts on behalf of purchasers of Sonus Networks,Inc. ("Sonus") (NASDAQ:SONS) common stock during the period betweenDecember 11, 2000 and January 16, 2002 (the "Class Period").

If you wish to serve as lead plaintiff, you must move the Court nolater than 60 days from today. If you wish to discuss this action orhave any questions concerning this notice or your rights or interests,please contact plaintiff's counsel, Samuel H. Rudman or David A.Rosenfeld of Lerach Coughlin at 800/449-4900 or 619/231-1058 or viae-mail at wsl@lerachlaw.com. If you are a member of this class, youcan view a copy of the complaint as filed or join this class actiononline at http://www.lerachlaw.com/cases/sonus/. Any member of thepurported class may move the Court to serve as lead plaintiff throughcounsel of their choice, or may choose to do nothing and remain anabsent class member.

The complaint charges Sonus Networks and certain of its officersand directors with violations of the Securities Exchange Act of 1934.Sonus is a telecommunications company with a relatively small numberof customers, all of which are large-scale communications serviceproviders.

The complaint alleges that throughout the Class Period, Defendantsknowingly or recklessly issued a series of materially false andmisleading statements that misled the investing public about Sonus'sbusiness, operations, performance, and prospects, and, in particular,the quality and capabilities of its products. In fact, Sonus'sproducts did not meet industry standards for reliability and were notcapable of meeting Sonus's customers' requirements for transmittingvoice calls over packet-based networks.

As alleged in the complaint, on January 16, 2002, the last day ofthe Class Period, Sonus shocked the market by announcing fourthquarter and year end 2001 results. Actual net loss for the fourthquarter of 2001 was $13.4 million, or $0.07 per share, compared withan actual net loss for the fourth quarter of 2000 of just $6.3million, or $0.04 per share. Actual net loss for fiscal 2001 was$645.4 million, or $3.74 per share, compared with an actual net lossfor fiscal 2000 of only $50.0 million, or $0.52 per share. Defendantsfinally stopped claiming that Sonus provided "carrier-class" products,and that its products "enable(d) service providers to deploy anintegrated network capable of carrying both voice and data traffic."

On this news, the following day Sonus's stock price dropped below$5, from a Class Period high of $45.88 on January 31, 2001. Volume was20,640,000 shares, compared to an average daily trading volume duringthe Class Period of 6,259,735.

Plaintiff seeks to recover damages on behalf of all purchasers ofSonus Networks common stock during the Class Period (the "Class"). Theplaintiff is represented by Lerach Coughlin, which has expertise inprosecuting investor class actions and extensive experience in actionsinvolving financial fraud.

Lerach Coughlin, a 160-lawyer firm with offices in San Diego, SanFrancisco, Los Angeles, New York, Boca Raton, Washington, D.C.,Houston, Philadelphia and Seattle, is active in major litigationspending in federal and state courts throughout the United States andhas taken a leading role in many important actions on behalf ofdefrauded investors, consumers, and companies, as well as victims ofhuman rights violations. Lerach Coughlin lawyers have been responsiblefor more than $20 billion in aggregate recoveries. The Lerach CoughlinWeb site (http://www.lerachlaw.com) has more information about thefirm.